TWI392412B - Circuit board and its manufacturing method - Google Patents

Description

Circuit board and manufacturing method thereof

The present invention relates to a circuit board and a method of fabricating the same, and more particularly to a circuit board having a chamber and a method of fabricating the same.

With the advancement of technology, the advent of mobile phones makes it easy for people to talk, making modern people able to enjoy the convenience of communication at any time. Therefore, mobile phones have become an indispensable tool for modern people.

The mobile phone usually includes a circuit board and a speaker (Speaker, also called a speaker). The wiring board has upper and lower surfaces opposite to each other, and the speaker is mounted on the upper surface. When the phone plays ringtones or music through the speaker, the speaker emits sound away from the board.

It can be seen that the sound of the speaker is emitted directly from the upper surface rather than directly from the lower surface. Therefore, the sound of the speaker usually needs to be transmitted indirectly to the lower surface through reflection.

The present invention provides a circuit board having a chamber that can be used to transmit sound.

The present invention further provides a wiring board that can be applied to an electronic device having electro-acoustic transducers.

The present invention further provides a method of manufacturing a wiring board for manufacturing the above wiring board.

The invention provides a circuit board comprising an insulating layer, a cavity shell and at least one circuit layer. The insulating layer has an outer surface and a plurality of holes in the outer surface. The cavity is embedded in the insulating layer and surrounds a chamber. The chamber housing has a plurality of openings in communication with the chamber, wherein the openings are in direct communication with the holes, respectively. The circuit layer is disposed on the outer surface.

In an embodiment of the invention, the outer surface includes an upper surface, a lower surface opposite to the upper surface, and a side surface connected between the upper surface and the lower surface, wherein one of the holes is located on the upper surface.

In an embodiment of the invention, at least two holes are located on the upper surface.

In an embodiment of the invention, another hole is located on the lower surface.

In an embodiment of the invention, the number of the circuit layers is two, and the circuit layers are respectively located on the upper surface and the lower surface.

In an embodiment of the invention, the at least one hole has an opening that exposes a portion of the cavity.

In an embodiment of the invention, the opening is more exposed to a portion of the insulating layer.

In an embodiment of the invention, the material of the cavity shell is metal, ceramic, plastic or rubber.

In an embodiment of the invention, the cavity shell has a tubular shape.

In an embodiment of the invention, the insulating layer comprises a first insulating material layer and a second insulating material layer, and the cavity shell is sandwiched between the first insulating material layer and the second insulating material layer.

In an embodiment of the invention, the first insulating material layer and the second insulating material layer are both a resin layer.

In an embodiment of the invention, the resin layer is a prepreg or a blank core.

The invention further provides a circuit board comprising an insulating layer, a cavity shell and at least one circuit layer. The insulating layer has an outer surface and at least one hole in the outer surface. The cavity is embedded in the insulating layer and surrounds a chamber. The chamber housing has a plurality of openings in communication with the chamber, one of the openings being in direct communication with the aperture and the other opening being located on the outer surface. The circuit layer is disposed on the outer surface.

In an embodiment of the invention, the opening on the outer surface is on a side surface.

In an embodiment of the invention, the number of the holes is plural, and the holes are located on the outer surface.

The invention further provides a method of manufacturing a circuit board, comprising providing a substrate, wherein the substrate comprises a first conductor layer and a first insulating material layer on the first conductor layer. Next, a cavity is disposed on the first layer of insulating material, wherein the cavity surrounds a chamber. Next, a second insulating material layer is formed, wherein the second insulating material layer covers the cavity and the first insulating material layer, and the first insulating material layer and the second insulating material layer form an insulating layer. Next, the first conductor layer is patterned. After patterning the first conductor layer, at least one hole is formed in an outer surface of the insulating layer, wherein the hole is in communication with the chamber.

In an embodiment of the invention, before the cavity is disposed, a recess is formed on the first insulating material layer, wherein the cavity is disposed in the recessed region.

In an embodiment of the invention, the recessed region is formed by laser ablation or routing.

In an embodiment of the invention, the first insulating material layer is a blank core layer.

In an embodiment of the invention, the second insulating material layer is a semi-cured film.

In an embodiment of the invention, after patterning the first conductor layer, the insulating layer and the cavity are further cut to expose the chamber.

In an embodiment of the invention, the method of cutting the insulating layer and the cavity comprises V-cut or milling.

In an embodiment of the invention, the number of the holes is plural, and the holes are formed on the outer surface and communicate with the chamber.

In an embodiment of the invention, the hole is a Non-Plate Through Hole (NPTH).

In an embodiment of the invention, the above method of forming an unplated through hole includes mechanical drilling or laser drilling.

In an embodiment of the invention, the method for manufacturing the circuit board further includes forming a second conductor layer on the second insulating material layer before patterning the first conductor layer. When the first conductor layer is patterned, the second conductor layer is patterned.

In an embodiment of the invention, the outer surface includes an upper surface and a lower surface opposite to the upper surface, and a protective layer is formed on the upper surface and the lower surface, respectively, before the holes are formed.

In an embodiment of the invention, the protective layers are two solder mask layers, and the solder resist layers are formed by printing.

Since the plurality of holes of the insulating layer can communicate with each other through the chamber, the outside air can flow in the holes and the chamber, so the holes and the chamber can transmit sound, and the circuit board of the present invention can be applied to have electroacoustic sound. The electronic device of the transducer.

The following specific embodiments are described in detail below with reference to the accompanying drawings.

1A is a cross-sectional view showing a circuit board according to an embodiment of the present invention. Referring to FIG. 1A, the circuit board 100 can be installed in a mobile phone, a Personal Digital Assistant (PDA), a digital audio player (Digital Audio Player, DAP, which is, for example, an MP3 player), and a palm-type amusement instrument ( An electronic device with an electroacoustic transducer, such as a handheld game console), a laptop or an ultra-mobile PC (UMPC).

The above-mentioned electroacoustic transducer generally refers to a transducer capable of converting electrical energy into acoustic energy or converting acoustic energy into electrical energy, and the electroacoustic transducer is, for example, a speaker (also called a speaker) or a microphone (microphone). , also known as the microphone).

The circuit board 100 includes an insulating layer 110, a cavity 120 and a plurality of wiring layers 130. The insulating layer 110 has an outer surface 110a and a plurality of holes H1, H2, wherein the holes H1, H2 are located on the outer surface 110a, and the circuit layers 130 are disposed on the outer surface 110a. The cavity 120 is buried in the insulating layer 110 and surrounds a chamber C1. The chamber casing 120 has a plurality of openings 120a communicating with the chamber C1, and these openings 120a are in direct communication with the holes H1, H2, respectively.

The outer surface 110a of the insulating layer 110 includes an upper surface S1, a lower surface S2 and a side surface S3, wherein the lower surface S2 is opposite to the upper surface S1, and the side surface S3 is connected between the upper surface S1 and the lower surface S2. In the embodiment shown in FIG. 1A, the number of the circuit layers 130 is two, and the circuit layers 130 are respectively located on the upper surface S1 and the lower surface S2, so that the circuit board 100 shown in FIG. 1A is a double-sided circuit board ( Double-side wiring board).

However, it must be noted that in other embodiments not shown, the number of circuit layers 130 may be one layer or more than three layers. That is, the circuit board 100 may be a single-side wiring board or a multi-layer wiring board. Therefore, the number and types of the circuit layers 130 shown in FIG. 1A are for illustrative purposes only and are not intended to limit the technical features of the present invention.

The apertures of both holes H1, H2 may be substantially the same, and in the embodiment shown in Fig. 1A, the total number of holes H1, H2 is four, two holes H1 are located on the upper surface S1, and two holes H2 are located Lower surface S2. That is to say, the opposite surfaces (i.e., the upper surface S1 and the lower surface S2) of the insulating layer 110 are provided with holes H1, H2.

In other embodiments not shown, the insulating layer 110 has a total number of holes H1, H2 of at least two. For example, the insulating layer 110 may have only two holes H1 or holes H2 located on the same surface (ie, the upper surface S1 or the lower surface S2); or, the upper surface S1 and the lower surface S2 may have only one hole H1, respectively. With a hole H2.

In view of the above, of course, the total number of holes H1, H2 may also be three or more than four. In addition, in other embodiments not shown, the insulating layer 110 may also have at least one hole located at the side surface S3 and communicating with the chamber C1. Therefore, the number and distribution of the holes H1, H2 shown in FIG. 1A are for illustrative purposes only and are not intended to limit the technical features of the present invention.

The material of the cavity shell 120 may be metal, ceramic, plastic or rubber, and the shape of the cavity shell 120 may be a tubular body, wherein the cavity shell 120 may be a tubular body that is substantially not curved and has a linear shape, as shown in the figure. 1A is shown. Of course, the cavity 120 can also be bent. For example, in other embodiments not shown, the shape of the cavity 120 can be a tubular shape of an L shape, a U shape, a wave shape, or a zigzag shape.

The insulating layer 110 may include a first insulating material layer 112a and a second insulating material layer 112b, and the cavity shell 120 is sandwiched between the first insulating material layer 112a and the second insulating material layer 112b. The material of the first insulating material layer 112a and the second insulating material layer 112b may be an insulating material such as a resin. For example, the first insulating material layer 112a and the second insulating material layer 112b may both be a resin layer, wherein the resin layer is, for example, a half. Cured film or blank core layer.

Both the first insulating material layer 112a and the second insulating material layer 112b may be resin layers of the same material, for example, the first insulating material layer 112a and the second insulating material layer 112b are both semi-cured films. Of course, the first insulating material layer 112a and the second insulating material layer 112b may also be resin layers of different materials, for example, the first insulating material layer 112a is a blank core layer, and the second insulating material layer 112b is a semi-cured film.

In summary, since the openings 120a communicate with the chamber C1 and the holes H1 and H2, all the holes H1 and H2 can communicate with each other through the chamber C1, so that outside air can be in the holes H1, H2 and the cavity. The chamber C1 flows, and a plurality of paths capable of transmitting sound are formed in the holes H1, H2 and the chamber C1.

In detail, at least one electroacoustic transducer 10 can be assembled on the circuit layer 130 of the circuit board 100 and located at one of the holes H1, wherein the electroacoustic transducer 10 has a transducing surface capable of receiving or emitting sound. The transduction surface 12 is assembled to the circuit board 100 through a jack, spring, and soldering.

When the electroacoustic transducer 10 is a speaker, the transducing surface 12 is a sound emitting surface and can emit sound toward the hole H1, wherein the speaker is, for example, a Microelectromechanical Systems Speaker (MEMS Speaker), and the sound can pass through the cavity. The chamber C1 is emitted from these holes H2 and other holes H1.

Thus, the sound of the electroacoustic transducer 10 can be directly emitted not only from the upper surface S1 but also directly from the lower surface S2 via the chamber C1 and the hole H2. In addition, in the present embodiment, the electroacoustic transducer 10 may further include a mask 14 disposed with respect to the transducing surface 12, and the mask 14 allows sound concentration to be transmitted toward the hole H1.

The electroacoustic transducer 10 may be a microphone in addition to the speaker, and the transducing surface 12 may be a sound receiving surface that receives sound. In detail, when the electroacoustic transducer 10 is a microphone and the external sound is transmitted to the circuit board 100, the transducing surface 12 can receive sound through the holes H1, H2 and the chamber C1, and convert the sound into electric energy, thereby The function of recording is achieved.

In addition, in other embodiments not shown, when the electroacoustic transducer 10 is a microphone, the hole H1 corresponding to the transducing surface 12 can pass through the chamber C1 and communicate with only the other hole H1 or H2. Therefore, the microphone type electroacoustic transducer 10 can receive sound from only two holes (ie, any two of the holes H1, H2) and a single strip formed by the chamber C1 to enhance the recording. Quality.

It should be noted that in other embodiments not shown, the number of electro-acoustic transducers 10 may be multiple, and these electro-acoustic transducers 10 may be respectively disposed at the holes H1, H2, wherein these The types of electroacoustic transducers 10 are not necessarily identical.

For example, the electroacoustic transducers 10 can be tweeters and woofers, and through the holes H1, H2 and the chamber C1 of the circuit board 100, the electroacoustic transducers 10 can generate a surround sound audible effect, providing Users have better hearing enjoyment. In addition, these electro-acoustic transducers 10 can also be a speaker and a microphone, that is, both the speaker and the microphone can be assembled on the same circuit board 100.

FIG. 1B is a schematic top view of the circuit board of FIG. 1A. Referring to FIG. 1A and FIG. 1B, each of the holes H1 has a hole T1, and the hole T1 of at least one of the holes H1 not only exposes part of the cavity 120 but also partially exposes the insulating layer 110. For example, the aperture D of the hole H1 is larger than the width W of the cavity 120 such that the opening T1 exposes a portion of the insulating layer 110.

However, in other embodiments, the opening T1 may also expose only a portion of the cavity 120 without exposing the insulating layer 110. For example, please refer to FIG. 1C , which is a top plan view of a circuit board according to another embodiment of the present invention. In the embodiment shown in Fig. 1C, the aperture D' of the hole H1' is smaller than the width W of the cavity 120, so that the opening T1' of the hole H1' exposes only a portion of the cavity 120, and the insulating layer 110 is not exposed.

It should be noted that each hole H2 also has a hole T2, and the apertures of both the holes H1 (or H1') and the holes H2 may be substantially the same, and the hole T2 of at least one hole H2 may expose a part of the cavity 120. And a portion of the insulating layer 110 (such as the opening T1 shown in FIG. 1B). Alternatively, the opening T2 may expose only a portion of the cavity 120 without exposing the insulating layer 110 (the opening T1' as shown in Fig. 1C).

2A to 2F are schematic cross-sectional views showing the process of manufacturing the circuit board of FIG. 1A. Referring to FIG. 2A, regarding the manufacturing method of the circuit board 100, first, a substrate 102 is provided, wherein the substrate 102 includes a first conductor layer 132a and a first insulating material layer 112a. The first insulating material layer 112a is on the first conductor layer 132a, and the first conductor layer 132a may be a metal layer, which is, for example, a copper foil.

Referring to FIG. 2A and FIG. 2B, a recessed region R1 is formed on the first insulating material layer 112a. Specifically, the first insulating material layer 112a may be a harder insulating material such as a blank core layer, and the recessed region R1 may be formed by laser ablation or milling.

Referring to FIG. 2C, after the recessed region R1 is formed, the cavity 120 is disposed on the first insulating material layer 112a, wherein the cavity 120 surrounds the chamber C1 and is disposed in the recessed region R1. The recessed area R1 will confine the cavity 120 to reduce the chance of the circuit board 100 being reworked or scrapped due to the movement of the cavity 120.

It should be noted that, in other embodiments not shown, the cavity 120 may also be disposed on the first insulating material layer 112a having no recessed region R1. In detail, the first insulating material layer 112a may also be a softer insulating material such as a prepreg, and the cavity 120 may be directly disposed on the first insulating material layer 112a. Therefore, the present embodiment does not necessarily have to perform the process of forming the recessed region R1, that is, the formation of the recessed region R1 is not an essential technical means of the present invention.

Referring to FIG. 2D, a second insulating material layer 112b is formed, wherein the second insulating material layer 112b covers the cavity 120 and the first insulating material layer 112a, and the second insulating material layer 112b may cover the cavity 120 in a comprehensive manner. And a first insulating material layer 112a. Further, the first insulating material layer 112a and the second insulating material layer 112b can form the insulating layer 110.

In detail, the second insulating material layer 112b may be a semi-cured film and can be formed by pressing, wherein the pressing process can be performed in a heating manner. That is, the second insulating material layer 112b may be formed on the cavity 120 and the first insulating material layer 112a via thermal compression bonding. Therefore, the second insulating material layer 112b can adhere to the cavity 120 and the first insulating material layer 112a, and the first insulating material layer 112a and the second insulating material layer 112b can be combined to form the insulating layer 110.

When the second insulating material layer 112b is formed, a second conductive layer 132b may be formed on the second insulating material layer 112b, wherein the materials of the second conductive layer 132b and the first conductive layer 132a may be the same. That is, the second conductor layer 132b may be a metal layer such as a copper foil.

Referring to FIG. 2D and FIG. 2E, the first conductor layer 132a and the second conductor layer 132b are patterned to form a two-layer wiring layer 130 partially exposing the upper surface S1 and the lower surface S2. The first conductor layer 132a and the second conductor layer 132b can be patterned simultaneously. That is, when the first conductor layer 132a is patterned, the second conductor layer 132b is also patterned. Further, the above patterning method may employ lithography and etching.

Referring to FIG. 2E and FIG. 2F, after forming the circuit layers 130, a plurality of holes H1, H2 are formed on the outer surface 110a of the insulating layer 110, wherein the holes H1, H2 are all in communication with the chamber C1. At this point, the circuit board 100 has been substantially completed.

These holes H1, H2 may be non-plated through holes, and methods of forming non-plated through holes include mechanical drilling or laser drilling. In other words, the holes H1, H2 may be formed via mechanical drilling or laser drilling. Further, the holes H1 and H2 may be formed on the upper surface S1 and the lower surface S2, respectively. In addition, in other embodiments not shown, at least one hole may be formed in the side surface S3.

In addition, in the embodiment not shown, before the holes H1 and H2 are formed, two protective layers may be formed on the upper surface S1 and the lower surface S2, respectively, wherein the protective layers cover the circuit layers 130 to protect these. Circuit layer 130. The above two protective layers may be two solder masks, and the solder resist layer may be formed by printing. Since the solder resist layer is formed before the holes H1 and H2 are formed, it is possible to prevent the solder resist material such as the solder resist ink from dripping into the chamber C1 during the printing process, thereby preventing the chamber C1 from being damaged.

3 is a cross-sectional view showing a circuit board according to another embodiment of the present invention. Referring to FIG. 3, the circuit board 200 includes an insulating layer 110, a cavity 220, and a multilayer wiring layer 130. The cavity 220 is embedded in the insulating layer 110 and surrounds a cavity C2. The circuit layer 130 is disposed on the outer surface 110a of the insulating layer 110. The shape and material of the cavity 220 are the same as the cavity 120 of the foregoing embodiment. Therefore, it will not be repeated.

The circuit board 200 of the present embodiment is similar to the circuit board 100 of the previous embodiment, and the main difference between the two is that the cavity 220 has an opening 220b on the outer surface 110a.

In detail, the chamber casing 220 has a plurality of openings 220a, 220b communicating with the chamber C2, wherein each opening 220a is in direct communication with the hole H1 or H2, and the opening 220b is located at the outer surface 110a. Thus, the outer surface 110a can directly expose the chamber C2 and a portion of the chamber shell 220 from the opening 220b. In addition, in the embodiment shown in FIG. 3, the outer surface 110a includes an upper surface S1, a lower surface S2, and a side surface S3, and the opening 220b is located at the side surface S3.

The electroacoustic transducer 10 can be assembled on the circuit layer 130 of the circuit board 200 and positioned at one of the holes H1, wherein the electroacoustic transducer 10 can be a speaker or a microphone, and the electroacoustic transducer 10 and the circuit board The assembly manner between 200 is the same as that of the foregoing embodiment, and therefore will not be described again.

When the electroacoustic transducer 10 is a speaker, the transducing surface 12 can emit sound toward the hole H1. This sound can be emitted from the other holes H1, H2 and the opening 220b of the chamber casing 220 via the chamber C2. Therefore, the sound emitted by the electroacoustic transducer 10 can be directly emitted from the upper surface S1, the lower surface S2, and the side surface S3.

The electroacoustic transducer 10 can be a microphone in addition to the speaker. In detail, when the electroacoustic transducer 10 is a microphone and the external sound is transmitted to the circuit board 200, the transducing surface 12 can receive sound from the holes H1, H2 and the opening 220b, and convert the sound into electric energy, thereby achieving The function of recording.

In addition, in other embodiments not shown, when the electroacoustic transducer 10 is a microphone, the hole H1 corresponding to the transducing surface 12 can pass through the chamber C2 and communicate only with the opening 220b. That is to say, the microphone type electroacoustic transducer 10 can only receive sound from the opening 220b to improve the quality of the recording.

It should be noted that, in other embodiments not shown, the number of electroacoustic transducers 10 may be multiple, and the electroacoustic transducers 10 may be disposed at the holes H1, H2, respectively. For example, these electro-acoustic transducers 10 can be tweeters and woofers. These electroacoustic transducers 10 can produce an audible effect of surround sound through the holes H1, H2 of the circuit board 200 and the chamber C2. In addition, these electroacoustic transducers 10 can also be speakers and microphones.

In other embodiments not shown, the circuit board 200 may include only one layer or more than three layers, that is, the circuit board 200 may be a single-sided circuit board or a multi-layer circuit board. Furthermore, the total number of holes H1, H2 of the insulating layer 110 may be one, two or more. Therefore, the circuit board 200 shown in FIG. 3 is for illustrative purposes only and is not intended to limit the technical features of the present invention.

It is worth mentioning that the hole H1 and the hole H2 respectively have a hole T1 and a hole T2, wherein the hole T1 and the hole T2 not only expose part of the cavity 220 but also partially expose the insulating layer 110 (such as the hole T1 shown in FIG. 1B). Of course, both the opening T1 and the opening T2 can also expose a portion of the cavity 220 without exposing the insulating layer 110, like the opening T1' shown in FIG. 1C.

The manufacturing method of the wiring board 200 of the present embodiment is similar to the manufacturing method of the wiring board 100 of the foregoing embodiment, and a method of manufacturing the wiring board 200 will be described below with reference to FIGS. 4A and 4B.

4A-4B are schematic cross-sectional views showing the process of manufacturing the circuit board of FIG. 3. Referring to FIGS. 4A and 4B, after the first insulating material layer 112a, the second insulating material layer 112b, and the wiring layers 130 are formed, the insulating layer 110 and the cavity 220 are cut to expose the chamber C2. At this point, the circuit board 200 has been substantially completed.

The method of cutting the insulating layer 110 and the cavity 220 may be V-cutting or milling. As such, a portion of the insulating layer 110 and a portion of the chamber shell 220 are cut away to expose the chamber C2 and form an opening 220b. In the present embodiment, the first insulating material layer 112a, the second insulating material layer 112b, and the circuit layer 130 are formed in the same manner as the foregoing embodiment, and thus will not be described again.

In summary, since the holes of the insulating layer can communicate with each other through the chamber, the outside air can flow in the holes and the chamber, thereby forming one or more paths capable of transmitting sound, and thus the electroacoustic transducer The emitted sound can be transmitted through the holes and the chamber from anywhere on the outer surface of the insulating layer; or the electroacoustic transducer can receive sound from the holes and the chamber.

Secondly, the circuit board of the present invention can simultaneously mount a tweeter and a woofer, and the sound emitted by both the tweeter and the woofer can be emitted from the holes and the chamber to generate an audible effect of the surround sound, thereby providing the user with more Good hearing enjoyment.

While the present invention has been described above in the foregoing embodiments, it is not intended to limit the invention, and the equivalents of the modifications and retouchings are still in the present invention without departing from the spirit and scope of the invention. Within the scope of patent protection.

10. . . Electroacoustic transducer

12. . . Transducing surface

14. . . Mask

100, 200. . . circuit board

102. . . Substrate

110. . . Insulation

110a. . . The outer surface

112a. . . First insulating material layer

112b. . . Second insulating material layer

120, 220. . . Cavity shell

120a, 220a, 220b. . . Opening

130. . . Circuit layer

132a. . . First conductor layer

132b. . . Second conductor layer

C1, C2. . . Chamber

D, D’. . . Aperture

H1, H1', H2. . . Hole

R1. . . Sag area

S1. . . Upper surface

S2. . . lower surface

S3. . . Side surface

T1, T1', T2. . . Hole

W. . . width

1A is a cross-sectional view showing a circuit board according to an embodiment of the present invention.

FIG. 1B is a schematic top view of the circuit board of FIG. 1A.

FIG. 1C is a schematic top view of a circuit board according to another embodiment of the present invention.

2A to 2F are schematic cross-sectional views showing the process of manufacturing the circuit board of FIG. 1A.

3 is a cross-sectional view showing a circuit board according to another embodiment of the present invention.

4A-4B are schematic cross-sectional views showing the process of manufacturing the circuit board of FIG. 3.

10. . . Electroacoustic transducer

12. . . Transducing surface

14. . . Mask

100. . . circuit board

110. . . Insulation

110a. . . The outer surface

112a. . . First insulating material layer

112b. . . Second insulating material layer

120. . . Cavity shell

120a. . . Opening

130. . . Circuit layer

C1. . . Chamber

H1, H2. . . Hole

S1. . . Upper surface

S2. . . lower surface

S3. . . Side surface

T1, T2. . . Hole

Claims (42)

A circuit board comprising: an insulating layer having an outer surface and a plurality of holes in the outer surface; a cavity shell embedded in the insulating layer and surrounding a chamber having a plurality of chambers Openings communicating with the chamber, wherein the openings are in direct communication with the holes; and at least one circuit layer disposed on the outer surface. The circuit board of claim 1, wherein the outer surface comprises an upper surface, a lower surface opposite to the upper surface, and a side surface connected between the upper surface and the lower surface, one of The hole is located on the upper surface. The circuit board of claim 2, wherein at least two holes are located on the upper surface. The circuit board of claim 2, wherein another hole is located on the lower surface. The circuit board of claim 2, wherein the number of the circuit layers is two, and the circuit layers are respectively located on the upper surface and the lower surface. The circuit board of claim 1, wherein at least one of the holes has a hole that exposes a portion of the cavity. The circuit board of claim 6, wherein the opening is more exposed to the insulating layer. The circuit board of claim 1, wherein the material of the cavity is metal, ceramic, plastic or rubber. The circuit board of claim 1, wherein the cavity is shaped as a tubular body. The circuit board of claim 1, wherein the insulating layer comprises a first insulating material layer and a second insulating material layer, and the cavity shell is sandwiched between the first insulating material layer and the second insulating layer Between layers of material. The circuit board of claim 10, wherein the first insulating material layer and the second insulating material layer are each a resin layer. The circuit board of claim 11, wherein the resin layer is a semi-cured film or a blank core layer. A circuit board comprising: an insulating layer having an outer surface and at least one hole in the outer surface; a cavity shell embedded in the insulating layer and surrounding a chamber having a plurality of chambers An opening communicating with the chamber, wherein one opening is in direct communication with the hole and the other opening is located on the outer surface; and at least one circuit layer is disposed on the outer surface. The circuit board of claim 13, wherein the outer surface comprises an upper surface, a lower surface opposite to the upper surface, and a side surface connected between the upper surface and the lower surface, the hole Located on the upper surface. The circuit board of claim 14, wherein the number of the circuit layers is two, and the circuit layers are respectively located on the upper surface and the lower surface. The circuit board of claim 14, wherein the opening on the outer surface is located on the side surface. The circuit board of claim 14, wherein the number of the holes is plural, and the holes are located on the outer surface. A circuit board according to claim 17, wherein one hole is located on the upper surface and the other hole is located on the lower surface. The circuit board of claim 17, wherein at least two holes are located on the upper surface. The circuit board of claim 13, wherein the hole has an opening that exposes a portion of the cavity. The circuit board of claim 20, wherein the opening is more exposed to the insulating layer. The circuit board of claim 13, wherein the material of the cavity is metal, ceramic, plastic or rubber. The circuit board of claim 13, wherein the cavity is shaped as a tubular body. The circuit board of claim 13, wherein the insulating layer comprises a first insulating material layer and a second insulating material layer, and the cavity shell is sandwiched between the first insulating material layer and the second insulating layer Between layers of material. The circuit board of claim 24, wherein the first insulating material layer and the second insulating material layer are each a resin layer. The circuit board of claim 25, wherein the resin layer is a semi-cured film or a blank core layer. A method of manufacturing a circuit board, comprising: providing a substrate, wherein the substrate comprises a first conductor layer and a first insulating material layer on the first conductor layer; and configuring a cavity on the first insulating material layer Wherein the cavity encloses a chamber; forming a second layer of insulating material, wherein the second layer of insulating material covers the cavity and the first layer of insulating material, and the first layer of insulating material and the second insulating material Forming an insulating layer; patterning the first conductor layer; and after patterning the first conductor layer, forming at least one hole in an outer surface of the insulating layer, wherein the hole is in communication with the chamber. The method for manufacturing a circuit board according to claim 27, further comprising forming a recessed region on the first insulating material layer before the cavity is disposed, wherein the cavity is disposed in the recessed region. The method of manufacturing a circuit board according to claim 28, wherein the recessed area is formed by laser ablation or milling. The method of manufacturing a circuit board according to claim 27, wherein the first insulating material layer is a blank core layer. The method of manufacturing a circuit board according to claim 27, wherein the second insulating material layer is a semi-cured film. The method of manufacturing a circuit board according to claim 27, after patterning the first conductor layer, further comprising cutting the insulating layer and the cavity to expose the chamber. The method of manufacturing a wiring board according to claim 32, wherein the method of cutting the insulating layer and the cavity comprises V-cutting or milling. The method of manufacturing a circuit board according to claim 27, wherein the number of the holes is plural, and the holes are formed on the outer surface and are in communication with the chamber. The method of manufacturing a circuit board according to claim 27, wherein the material of the cavity is metal, ceramic, plastic or rubber. The method of manufacturing a wiring board according to claim 27, wherein the shape of the cavity is a tubular body. The method of manufacturing a circuit board according to claim 27, wherein the hole is an electroless through hole. The method of manufacturing a circuit board according to claim 37, wherein the method of forming the non-plated through hole comprises mechanical drilling or laser drilling. The method of manufacturing a circuit board according to claim 27, further comprising: forming a second conductor layer on the second insulating material layer before patterning the first conductor layer; and when patterning the first When a conductor layer is formed, the second conductor layer is patterned. The method of manufacturing a circuit board according to claim 27, wherein the outer surface includes an upper surface and a lower surface opposite to the upper surface, and the upper surface and the lower surface are respectively formed before the hole is formed The surface forms a second protective layer. The method of manufacturing a circuit board according to claim 40, wherein the protective layers are two solder mask layers, and the solder resist layers are formed by printing. An electronic device comprising: a circuit board comprising: an insulating layer having an outer surface and a plurality of holes in the outer surface; a cavity shell embedded in the insulating layer and surrounding a chamber, the cavity shell Having a plurality of openings in communication with the chamber, wherein the openings are in direct communication with the holes; and at least one circuit layer disposed on the outer surface; and an electroacoustic transducer, the circuit assembled on the circuit board On the layer, and in one of the holes.